Supplemental seal for the chordal hinge seal in a gas turbine

Abstract

In a gas turbine having a chordal hinge seal between an inner rail of each nozzle segment and an annular axially facing sealing surface of a nozzle support ring, a supplemental seal is disposed between the support ring and inner rail of the nozzle segment on a high pressure side of the chordal hinge seal. The supplemental seal includes a pair of sheet metal shims overlaid by a woven metallic cloth supported by a bracket secured to the nozzle support ring. The radially outer end of the cloth seal bears against a back side of the inner rail. The shims of the legs of the supplemental seal are slit along their distal margin and staggered in a circumferential direction relative to one another to provide flexibility and effective sealing engagement with the inner rail.

What is claimed is:  
     
       1. A turbine comprising: 
       a turbine nozzle support ring having a generally axially facing first surface;  
       a turbine nozzle segment having at least one stator vane and a radially inwardly extending inner rail having a second surface in axial opposition to said first surface;  
       a seal extending from said turbine nozzle support ring for sealing engagement along a side surface of said inner rail remote from said second surface for sealing between said support ring and said nozzle segment; and  
       said seal including a seal segment having at least a first plate, an overlay of a woven metallic cloth and a distal margin covered by said cloth and engaging said remote side surfaced and wherein said inner rail has a projection extending axially therefrom for sealing engagement against said first surface and forming a second seal therewith.  
     
     
       2. A turbine according to  claim 1  wherein said seal segment includes a second plate, said plates lying back-to-back with one another, said cloth extending as an overlay along opposite sides of said first and second plates. 
     
     
       3. A turbine according to  claim 2  wherein said seal extends in an arcuate direction about an axis of the turbine, said plates having slits extending from edges thereof and along said margin to provide flexibility to said seal. 
     
     
       4. A turbine according to  claim 3  wherein the slits along a margin of said first plate and the slits along a margin of said second plate are staggered relative to one another about the axis. 
     
     
       5. A turbine according to  claim 1  wherein said projection extends linearly along said inner rail. 
     
     
       6. A turbine according to  claim 5  wherein said sealing engagement between said projection and said first surface lies on a low pressure side of the first-mentioned seal. 
     
     
       7. A turbine according to  claim 6  wherein the first seal extends in an arcuate direction about an axis of the turbine. 
     
     
       8. A turbine according to  claim 1  including a support bracket extending generally radially outwardly from said support ring to support said seal segment on a side thereof remote from said inner rail, said margin of said seal segment being flexible and preloaded to seal against said remote side surface. 
     
     
       9. A turbine according to  claim 8  wherein said first seal extends in an arcuate direction about an axis of the turbine, said support ring including an arcuate groove, and an edge of said bracket remote from said seal margin being disposed in said groove. 
     
     
       10. A turbine comprising: 
       a turbine nozzle support ring having a generally axially facing first surface;  
       a plurality of turbine nozzle segments each having at least one stator vane and a radially inwardly extending inner rail having a second surface in axial opposition to said first surface;  
       a seal comprised of a plurality of seal segments extending from said nozzle support ring for sealing engagement along a side surface of said inner rail remote from said second surface; and  
       each said seal segment including a first plate, an overlay of a woven metallic cloth and a distal margin covered by said cloth and engaging said remote side surface and wherein each said inner rail has a projection extending axially therefrom for sealing engagement against said first surface and forming a second seal therewith.  
     
     
       11. A turbine according to  claim 10  wherein each said seal segment includes a second plate, said first and second plates of each said seal segment lying back-to-back with one another, said cloth extending as an overlay along opposite sides of said first and second plates. 
     
     
       12. A turbine according to  claim 10  wherein each of said seal segments extends in an arcuate direction about an axis of the turbine and across an intersegment gap between said nozzle segments. 
     
     
       13. A turbine according to  claim 10  wherein each said seal segment includes a second plate, said first and second plates of each said seal segment lying back-to-back with one another, said cloth extending as an overlay along opposite sides of said first and second plates, each said seal extending arcuately about an axis of the turbine, said plates having slits extending from edges thereof and along said margin to provide flexibility to said seal. 
     
     
       14. A turbine according to  claim 13  wherein the slits along a margin of said first plate and the slits along a margin of said second plate in each seal segment are staggered relative to one another about the axis of the turbine. 
     
     
       15. A turbine according to  claim 10  wherein said projections extend linearly along said inner rails. 
     
     
       16. A turbine according to  claim 15  wherein said sealing engagement between said projections and said first surface lies on a low pressure side of the first-mentioned seal. 
     
     
       17. A turbine according to  claim 10  including a plurality of support brackets extending generally radially outwardly of said support ring to support said seal segments on said support ring, said margins of said seal segments being flexible and preloaded to seal against said remote surface. 
     
     
       18. A turbine according to  claim 17  wherein said seal segments extend in an arcuate direction about an axis of the turbine, said support ring including an arcuate groove, and an edge of each said bracket remote from said seal margin being disposed in said groove.